Protection against landmine explosion

ABSTRACT

A body and any occupant of a land vehicle ( 10 ) is protected against effects of a landmine explosion, by conducting shock waves laterally outwardly by means of one or more shock wave guide members ( 16, 18 ) of a material having high acoustic velocity, and located proximate a ground engaging element ( 12 ) of the vehicle. The material may be glass, ceramic or the like having an acoustic velocity of about 6000 m/sec or more, i.e. higher than other materials of other components of the land vehicle. Shock waves encounter less resistance in high-acoustic velocity materials and are thus conducted laterally outwardly, i.e. away from the body. The shock wave guide members may be located immediately above bottom runs of tracks ( 12 ) and annularly within wells of bogey wheels ( 14 ) of track vehicles; and annularly around hubs or within tyres of wheels of wheeled vehicles.

TECHNICAL FIELD

This invention relates to a method of protecting a body or hull and anyoccupant of a land vehicle, such as an armoured vehicle, e.g. anarmoured tank or car, against the effects of a landmine explosion, e.g.an anti-tank landmine explosion. It relates also to a land vehicle, andto a combination of a ground engaging element for a land vehicle and ashock wave guide member.

BACKGROUND OF THE INVENTION

When a vehicle sets off a landmine, generally the landmine explodesunderneath a ground engaging element such as a wheel or track of thevehicle because of the ground pressure created by said ground engagingelement on the landmine.

Japanese patent document having publication number 2002090095, disclosesan apparatus for removing a mine buried under the ground surface. Theapparatus includes a composite rotor having a plurality of generallycoaxial rollers loosely located with lost motion in a radial directionover a fixed axis shaft mounted on, so as spatially to lead, a vehicle.The rollers can individually follow contours, hollows, humps, etc. totrigger landmines. Behind the rotor there is provided a protective platescreening the landmine blast and protecting the vehicle and an occupant.

Japanese Patent document having a publication number 2002340499,discloses a rotor including a plurality of blades. The rotor is rotatedto cause the blades to cut into a ground surface to destroy mines. Acurved safety cover is provided over the rotor to protect the vehicleand a driver from sand, mud and landmine fragments. A lower levelgrader-like blade deflects sand, mud and mine fragments laterally toprovide a smooth running surface for the vehicle. It is notable that thevehicle is not intended to trigger landmines to explode, but to destroylandmines before explosion. The inventor thus did not anticipatelandmine explosions and resulting shock waves.

U.S. Pat. No. 5,442,990 discloses a scarifying drum leading a trackvehicle to explode landmines. A flap is provided over the drum to act asa shield.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention, there is provided amethod of protecting a body or hull and any occupant of a land vehiclemovable along a substrate on ground engaging elements against theeffects of a landmine explosion, including conducting shock wavesgenerated by the landmine explosion laterally outwardly by means of ashock wave guide member of a material having a relatively high acousticspeed and located proximate a ground engaging element of the vehicle.

For purposes of this specification, terms denoting direction, such asfore, rear, lateral, and the like should be interpreted with referenceto a normal direction of forward travel of a land vehicle. The term“laterally outward” means “sideways away from (the land vehicle)”.

By “relatively high” acoustic speed is meant an acoustic speed higherthan the acoustic speed of the metal used in components of the landvehicle. Such metal, e.g. steel, aluminum, and alloys thereof, generallyhave an acoustic speed of about 5000 m/sec.

The material of each shock wave guide member may be selected frommaterials including glass, a suitable ceramic such as an alumina, or thelike, which have an acoustic speed of higher than about 6000 m/sec. Someceramics may have acoustic speeds up to about 8000 m/sec.

When the vehicle is a track vehicle, the ground engaging elements beingin the form of tracks, the guide member may be located in at least oneof a well of a bogey wheel, i.e. an annular cavity surrounding a hub andradially inward of a rim of the bogey wheel; and immediately above abottom run of a track intermediate bogey wheels.

When the vehicle is a wheeled vehicle, the ground engaging elementsbeing in the form of wheels, the guide member may be located in a wellof at least one of the wheels. The method may include absorbing energyby means of a liquid provided in a tyre of the vehicle, in the case thatthe wheels have tyres.

In accordance with a second aspect of the invention, there is provided aland vehicle movable along a substrate on ground engaging elements,which land vehicle is adapted or converted to protect its body or hulland any occupant against the effects of a landmine explosion, the landvehicle comprising a plurality of shock wave guide members proximateground engaging elements thereof, the shock wave guide members beingoriented to conduct shock waves laterally outwardly away from the bodyor hull.

When the land vehicle is in the form of a track vehicle, the groundengaging elements being in the form of tracks, the guide members may bepositioned in wells of bogey wheels, as well as immediately above abottom run of each track intermediate bogey wheels. Those guide membersproximate tracks intermediate bogey wheels may have layers of lowfriction material, such as TEFLON, on their surfaces interfacing withthe tracks.

When the land vehicle is in the form of a wheeled vehicle, the groundengaging elements being in the form of wheels, the guide members may bepositioned annularly in wells of at least some of the wheels e.g. atleast fore wheels. When the wheels have hollow tyres around wheel rims,the guide members may be positioned annularly in the hollows of thetyres. By way of development, cavities within the tyres may be filledwith a liquid for absorbing some of the energy of the explosion. Theliquid may be selected to have an appropriate boiling point andcoefficient of latent heat of evaporation. It may, for example, bewater, glycerin, a mixture of water and glycerin, or the like.

The guide members may be of composite construction, each guide membercomprising a plurality of oriented or directed laminates of a materialhaving an acoustic speed of at least about 6000 m/sec. Such material maybe a primary material, e.g. a glass or ceramic material. The guidemember may be in laminated form comprising laminates of the primarymaterial interposed by an interface material having an acoustic speedlower than that of steel, the laminates being directed generally in saidlaterally outward and upward, oblique direction. The interface materialmay be a synthetic polymeric material. Said interface material may havean acoustic speed lower than that of air. The laminates may thus besandwiched in-between layers of material having a relatively lowacoustic speed, lower than about 1000 m/sec, even lower than theacoustic speed of air.

The laminates may be oriented to extend obliquely laterally outwardly inuse.

A respective guide member may be positioned annularly inward of a treadof the wheel. It may be annularly around a hub of the wheel. It ispreferably acoustically well coupled to a wheel frame (colloquiallyreferred to as a wheel rim).

The guide members may have surfaces which are profiled snugly to bereceived with little clearance, or even slight touching, on surfaces ofthe ground engaging elements.

In accordance with a third aspect of the invention, there is providedthe combination of a ground engaging element for a land vehicle and ashock wave guide member of a material having an acoustic speed of higherthan about 6000 m/sec, the guide member being locatable proximate aground engaging surface of the ground engaging element.

When the ground engaging element is a track and bogey wheel arrangementfor a track vehicle, the guide member may be adapted for location in oneof a well of a bogey wheel, and immediately above a lower run of thetrack intermediate bogey wheels.

When the ground engaging element is a wheel for a wheeled vehicle, theguide member may be adapted for location within a well of the wheel.

When the ground engaging element is a wheel, having a hollow tyre, for awheeled vehicle, the guide member may be adapted for location within thehollow of the tyre.

These and other features of the present application will become apparentto one of ordinary skill in the art upon review of the followingdetailed description when taken in conjunction with the drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described by way of examples with reference to theaccompanying diagrammatic drawings. In the drawings

FIG. 1 shows, in fragmentary side view, a track vehicle converted inaccordance with the invention;

FIG. 2 shows, to a larger scale, fragmentarily, a bogey wheel of thetrack vehicle of FIG. 1, converted in accordance with the invention;

FIG. 3 shows, in diametrical section, the bogey wheel of FIG. 2;

FIG. 4 shows, in cross section, to a larger scale, a guide memberproximate a track of the track vehicle of FIG. 1;

FIG. 5 shows, fragmentarily, in radial section, a first embodiment of awheel for a wheeled vehicle in accordance with the invention; and

FIG. 6 shows, in a view corresponding to that of FIG. 5, a secondembodiment of a wheel for a wheeled vehicle.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 to 4 of the drawings, a track vehicle in theform of an armoured tank is generally indicated by reference numeral 10.The track vehicle 10 has a pair of tracks 12 guided along a lower run ofeach track on bogey wheels 14. The track is shown fragmentarily only,and only one track 12 is shown, also fragmentarily.

In accordance with the invention, a first kind of guide member,generally indicated by reference numeral 16, is located within wells ofthe bogey wheels 14, i.e. annularly intermediate hubs 14.1 and rims 14.2of the respective bogey wheels 14.

In the event that the bogey wheel 14 has webs 14.3 at circumferentiallyspaced positions within said wells, the guide member 16 is in the formof a composite guide member comprising a plurality of segments 16.1shown in FIG. 2.

As can best be seen in FIG. 3, each segment has a plurality of laminates16.2 sandwiched in-between dividing layers 16.3 which may be of ayielding, even resilient, low acoustic speed material such aspolyurethane, rubber or the like. The laminates 16.2 are orientedlaterally outwardly.

In the event of a landmine explosion underneath the bogey wheel 14,shock waves generated by the landmine explosion will propagate throughthe track 12, through the rim 14.2 of the bogey wheel 14 immediatelyabove the track 12 and will be “loaded into” the respective segment orsegments 16.1. The Applicant has realized that shock waves encounterresistance to propagation inversely proportional to the acoustic speedof a material. Thus, in a material having a high acoustic speed likeglass, especially ceramics, such as that of the guide member 16, theshock waves are guided effectively laterally outwardly in accordancewith the orientation of the laminates. It is further to be appreciatedthat, should a component of the shock waves be conducted obliquely alongsuch a laminate, when it reaches a dividing layer 16.3 having a lowacoustic speed and thus offering high resistance to propagation of shockwaves, the shock waves are deflected back into the high acoustic speedmaterial which assists in guiding the shock waves laterally outwardly.

When the shock waves reach the surface of the guide member, andpreferably it should do so at approximately right angles, the shockwaves, when they encounter the neighbouring air, which has a lowacoustic speed, cause spalling of the material which results in afragment or fragments of material to be liberated and to be projectedgenerally in the direction of spalling i.e. laterally outwardly.

In this regard, the Applicant has realized that a blast effect generatedby the landmine explosion and following the shock waves in time,generally follows the path or route of least resistance. In this regard,the Applicant has further appreciated that the shock waves crack andpulverize the material of the guide member, but at a propagation speedsubstantially lower than the acoustic speed. Thus, the guide memberremains intact fully to propagate the shock waves, but immediatelybehind the shock waves, cracks and pulverizes to facilitate beingdisplaced or blown away by the blast effect. Thus, a route of lesserresistance is created in the direction in which the shock waves wereguided. Furthermore, the effect of spalling and of a fragment beingprojected from the outer surface creates a region of low pressure whichis followed by the blast effect.

Thus, the Applicant has realized that managing or guiding of the shockwaves in a predetermined direction away from a body of the track vehiclenot only protects the body against the effect of the shock waves, butalso that the blast effect tends to follow the leader shock waves andthat the body of the track vehicle is thus also protected against theeffects of the blast.

Similarly, with reference to FIG. 4, a guide member 18 comprises aplurality of laminates 18.2 sandwiched by dividing layers 18.3 ofpolyurethane, rubber, or the like. By way of development, the guidemember 18 is profiled at its interface with the track 12, to fit snuglyover the track 12, and even to rub against the track 12. To mitigatesuch rubbing, a rubbing surface 20 of a low friction material such asTeflon is provided at the interface.

The mechanism of guiding of the shock waves in the case of the guidemember 18 is exactly the same as that of the guide member 16 and alsothe creation of a route of lesser resistance is similar.

The Applicant believes that the invention provides a simple, elegant andrelatively inexpensive method of managing shock waves by directing orguiding the shock waves in a desired direction, and furthermore thatsuch guiding of the shock waves creates a route of lesser resistancewhich is followed by the blast in preference thus also protectingvulnerable and valuable parts of the vehicle against the effect not onlyof the shock waves, but also of the blast.

With reference to FIG. 5 of the drawings, a wheel in accordance with theinvention is generally indicated by reference numeral 110. The wheel 110is a solid wheel, i.e. not a neumatic wheel or inflatable wheel. It isgenerally of sturdy construction and suitable for use in traversing aminefield to detonate anti-personnel mines. It is to be understood thatit will be mounted to a vehicle. In accordance with the invention, thewheel 110 is suitable to protect a body or hull of the vehicle and thusalso an occupant of the vehicle against the effect of a powerfullandmine, such as an anti-tank mine, which may be encountered in a fieldof generally anti-personnel mines.

The wheel 110 comprises a wheel frame 112 having a hub 114 defining ahub volume 115 via which the wheel 110 is mounted to the vehicle in anyappropriate fashion. The wheel frame 112 comprises, at an outerperiphery thereof, a peripheral flange 116. A tread 118 in the form of ahoop of an appropriate grade of steel is mounted via the peripheralflange 16 to the wheel frame 112.

In accordance with the invention, in an annular space radially withinthe tread 118, there is provided a guide member 120 which isconveniently a composite member comprising a plurality of segments,together forming an annular construction.

Each section of the guide member 120 is of generally triangularcross-section comprising a plurality of laminates 122 with layers ofdividing material in the form of dividers 124 being sandwichedin-between adjacent laminates 122. The laminates 122 and the dividers124 form a parallel directed structure pointing radially inwardly andlaterally outwardly. If a bottom segment of the wheel 110 is viewed, thelaminates 122 and dividers 124 are directed obliquely upwardly andlaterally outwardly. It is to be appreciated that the side of the wheel110 having the wheel frame 112 will be proximate a body or hull of avehicle to which the wheel 110 is mounted. That side, indicated byreference numeral 140, will be referred to as the protected side, as thebody or hull, and the occupant of the vehicle are to be protectedagainst the effects of a landmine explosion taking place underneath thetread 118.

The laminates 122 are of a material having a high acoustic speed,whereas the dividers 124 are of a yielding, even resilient, materialhaving a low acoustic speed, such as a synthetic polymeric material, forexample polyurethaine, rubber, or the like.

In the event of a landmine explosion underneath the tread 118, shockwaves generated by the landmine explosion will propagate through thetread 118 and will be “loaded” into the guide member 120 via a surface126 thereof proximate the tread 118. The applicant has realized thatshock waves encounter resistance to propagation inversely proportionalto the acoustic speed of a material. Thus in a material having a highacoustic speed like glass, or especially ceramic, such as that of thelaminates 122, the shock waves are propagated well along such highacoustic speed material. It is further to be appreciated that thedividers 124 are of a material having a very low acoustic speed and thusoffering very high resistance to propagation. In fact, a combination ofa high acoustic speed material backed by a low acoustic speed materialacts as a mirror for shock waves, thus deflecting or reflecting theshock wave back into the high acoustic speed material. In the embodimentillustrated, it is expected that shock waves traveling generallydirectly upwardly through the tread 118 into the respective laminates122, will be guided obliquely laterally outwardly generally along thelaminates 122 as deflection or reflection takes place at each interfacebetween the respective laminates and their backing dividers 124. It isfurthermore to be appreciated that the laminate 122 at the extremity isflanked by air, which also has a low acoustic velocity and deflectingwill thus also take place along the extreme laminate 122.

Thus, it is expected that shock waves will be propagated obliquelyupwardly and laterally outwardly from the surface 126 to a lateralsurface 128 along an annular side of the guide member 120 and thustoward an outside, indicated by reference numeral 142 of the vehicle.

When the shock waves reach the surface 128 of the guide member 120, theshock waves, when they encounter the neighboring air, which has a lowacoustic speed, cause spalling of the material which results in afragment or fragments of material to be liberated and to be projectedgenerally in the direction of spalling, i.e. generally laterallyoutwardly, to create a route of lesser resistance and thus to induce theblast effect generated by the landmine explosion and following the shockwaves in time, generally to follow the path or route of lesserresistance, as described above.

With reference to FIG. 6, a further, developed embodiment of a wheel inaccordance with the invention is generally indicated by referencenumeral 210. In many respects, the wheel 210 resembles the wheel 110 andits construction and operation are not fully described again.

The wheel 210 includes a wheel frame 212 having an outer peripheral rim216 seating an inflatable tyre 219 having side walls 219.1 and a tread219.2. A steel tread 218 in the form of a hoop and of an appropriatelydurable material such as steel which is resistant to explosions ofanti-personnel mines, could be used. The steel tread 218 has, along sideedges thereof, laterally inwardly directed flanges 218.1 for seatingover the tyre tread 219.2 and thus to prevent the steel tread 218 fromunseating. It is to be appreciated that the steel tread 218 will bepositioned over the tyre 219 when the tyre is deflated.

Within the tyre 219, there is provided a guide member 220 similar to theguide member 120 of FIG. 5. The guide member 220 may be secured to therim 216 in any convenient and appropriate fashion, for example by meansof an annular, frame-like securing member 230 which is shownschematically. The guide member 220 has laminates 222 interposed bydividers 224 of materials similar to those described with reference toFIG. 5.

The mechanism of guiding of shock waves in the wheel 210 is similar tothat described with reference to FIGS. 1 to 5 and it is thus notrepeated.

By way of development, the volume within the tyre 219 is advantageouslyfilled by means of a liquid 232. The liquid 232 is selected to beeffective in absorbing energy associated with the landmine explosion.The liquid may have a relatively low boiling point and its latent heatof evaporation will be selected to absorb energy in the form of heat. Alayer of liquid between the steel tread 218, and the face 226, willpromote acoustic coupling and thus “loading” of the shock waves into theguide member 220.

It is to be appreciated that the wheel 210 of FIG. 6 has the advantagethat it has some resilience providing a suspension effect and is thusexpected to allow a vehicle to travel faster than a vehicle rollingalong wheels of the kind of FIG. 5.

The invention has the advantage that a vehicle shod with wheels fortraversing a minefield to detonate anti-personnel mines in theminefield, is protected against the effects of any high poweredlandmine, such as an anti-tank landmine, which may be laid in theminefield being cleared.

The invention is applicable in principle also in other kinds of wheels,for example, an annular guide member as described may be positioned

within a well of a wheel frame having a “soft” tyre, i.e. a pneumatictyre, a solid moulded tyre of rubber, polyurethane, or the like, whetheror not such a wheel has an outer hoop of steel or other explosionresistant material;

within a pneumatic tyre (tubed or tubeless) when the wheel does not havethe outer hoop as in FIG. 6;

moulded within a moulded solid tyre of rubber, polyurethane or the like,whether or not such a wheel has an outer hoop of steel or otherexplosion resistant material.

It should be apparent that the foregoing relates only to the preferredembodiments of the present application and that numerous changes andmodifications may be made herein without departing from the generalspirit and scope of the invention as defined by the following claims andthe equivalents thereof.

1. A method of protecting a body or hull and any occupant of a landvehicle movable along a substrate on ground engaging elements againstthe effects of a landmine explosion, including conducting shock wavesgenerated by the landmine explosion laterally outwardly by means of ashock wave guide member comprising a plurality of oriented laminates ofa material having a relatively high acoustic speed and located proximatea ground engaging element of the vehicle, the laminates being orientedto extend laterally outwardly.
 2. A method as claimed in claim 1 inwhich the material of each shock wave guide member is selected frommaterials including glass or a suitable ceramic which have an acousticspeed of higher than about 6000 m/sec.
 3. A method as claimed in claim2, in which the ceramic is an alumina.
 4. A method as claimed in claim 1in which the vehicle is a track vehicle, the ground engaging elementsbeing in the form of tracks, the guide members being located in at leastone of a well of a bogey wheel and immediately above a bottom run of atrack intermediate bogey wheels.
 5. A method as claimed in claim 1 inwhich the vehicle is a wheeled vehicle, the ground engaging elementsbeing in the form of wheels, the guide member being located in a well ofthe wheel.
 6. A land vehicle movable along a substrate on groundengaging elements, which land vehicle is adapted or converted to protectits body or hull and any occupant against the effects of a landmineexplosion, the land vehicle comprising a plurality of shock wave guidemembers proximate ground engaging elements of the land vehicle,characterized in that the shock wave guide members are of a materialhaving a relatively high acoustic speed higher than the acoustic speedof metal used in components of the land vehicle which components have anacoustic speed generally of about 5000 m/sec, the shock wave guidemembers comprising a plurality of laminates oriented to conduct shockwaves laterally outwardly away from the body or hull.
 7. A land vehicleas claimed in claim 6, in which is in the material of each shock waveguide member is selected from materials, including glass or a suitableceramic material which materials have an acoustic speed of higher thanabout 6000 m/sec.
 8. A land vehicle as claimed in claim 7, in which theceramic is an alumina.
 9. A land vehicle as claimed in claim 6 which isin the form of a track vehicle, the ground engaging elements being inthe form of tracks, in which the guide members are positioned in wellsof bogey wheels, as well as immediately above a bottom run of each trackintermediate bogey wheels.
 10. A land vehicle as claimed in claim 9 inwhich the guide members proximate tracks intermediate bogey wheels havelayers of low friction material on their surfaces interfacing with thetracks.
 11. A land vehicle as claimed in claim 6 which is in the form ofa wheeled vehicle, the ground engaging elements being in the form ofwheels, in which the guide members are positioned annularly in wells ofthe wheels.
 12. A land vehicle as claimed in claim 6 which is in theform of a wheeled vehicle, the ground engaging elements being in theform of wheels, each wheel having a hollow tire around a wheel rim, inwhich the guide members are positioned annularly in the hollows of thetires.
 13. A land vehicle as claimed in claim 6 in which the guidemembers are of composite construction, each guide member comprising aplurality of oriented or directed laminates of a material having anacoustic speed of at least about 6000 m/sec.
 14. A land vehicle asclaimed in claim 13 in which the laminates are sandwiched in-betweenlayers of material having a relatively low acoustic speed, lower thanabout 1000 m/sec.
 15. A land vehicle as claimed in claim 13 in which thelaminates are oriented to extend obliquely laterally outwardly in use.16. A land vehicle as claimed in claim 13 in which said guide membershave surfaces which are profiled snugly to be received with littleclearance, or even slight touching, on surfaces of the ground engagingelements.
 17. A ground engaging element for a land vehicle incombination with a shock wave guide member of a material having anacoustic speed of higher than about 6000 m/sec, the guide member beinglocatable proximate a ground engaging surface of the ground engagingelement and comprising a plurality of laminates oriented to conductshock waves laterally outwardly in use.
 18. A combination as claimed inclaim 17, in which the ground engaging element is a track and bogeywheel arrangement for a track vehicle, the guide member being adaptedfor location in one of a well of a bogey wheel, and immediately above alower run of the track intermediate bogey wheels.
 19. A combination asclaimed in claim 17, in which the ground engaging element is a wheel fora wheeled vehicle, the guide member being adapted for location within awell of the wheel.
 20. A combination as claimed in claim 17, in whichthe ground engaging element is a wheel, having a hollow tire, for awheeled vehicle, the guide member being adapted for location within thehollow of the tire.